The present invention relates to an ink cartridge that supplies ink to an inkjet printer.
In order to cope with requirements for mass printing, width enlargement, and speed increase, an inkjet printer provides an ink supply source independent of an inkjet head, adopts a system of supplying ink from the ink supply source through a tube, and uses an ink bag as the ink supply source in some case.
As an example of the inkjet printer constructed as described above, a construction is mentioned, in which the ink bag is received in a hard case to constitute an ink cartridge, an ink supply port provided on one end of the ink bag is connected to the tube, and the ink is introduced into the inkjet head through the tube, whereby the ink is supplied to the inkjet head. Further, a construction is also possible, in which a sub tank is provided between the ink cartridge and the inkjet head, whereby the supply of the ink to the inkjet head is not stopped immediately after the ink in the ink bag runs out.
When such an ink supply mode is constructed, a selectable range of a received position of the ink cartridge in the inkjet printer is increased, and in addition, an increase of a capacity of the ink cartridge, which meets the requirements for the inkjet printer to achieve the mass printing, the width enlargement, and the speed increase, also becomes easy. As a result, enlargement of the ink bag in terms of size and dimension is adopted.
Incidentally, as seen in Japanese Patent No. 3494014, as such an ink-cartridge, there is one that includes a reinforcement film in a peripheral portion of an ink supply port of a deformable ink bag, and prevents breakage of the ink bag even if the ink bag is enlarged in terms of size and dimension in response to the increase of the capacity of the ink cartridge.
In the case of using a hermetically sealed ink bag, the ink bag contracts in a process in which the ink is consumed. At this time, the ink bag cannot be sometimes deformed in accordance with a shape of an ink bag attaching portion of the hard case. Further, initial distortion of the ink bag owing to flexure and wrinkle of the ink bag, which are caused at the time when the ink bag of the ink cartridge is attached to the hard case, comes to largely affect the deformation of the ink bag. As a result, extreme deformation of only a part of the ink bag occurs, the distortion of the ink bag is promoted together with consumption of the ink, resulting in the deformation of the ink. Further, it becomes sometimes impossible to stably and sufficiently supply the ink in the ink bag to the inkjet head. Because of those problems, such a problem occurs that the ink in the ink bag cannot be fully used though a large amount thereof remains in the ink bag. Those problems have become prone to occur owing to the enlargement of the ink bag in terms of size and dimension, which follows the increase of the capacity of the ink cartridge.